Both Function in WEBI

Dear Experts,

We have one requirement example below.

Emp No    Name          Designation   Start Date     End Date

1              XXX             ADMIN   1/1/2015         1/10/2015

1              XXX             HR          1/5/2015         1/9/2015

2              YYY             HR          1/1/2015         1/10/2015

Now we need to display employees with a single designation. Out should be like i need to display


Emp No    Name          Designation   Start Date     End Date

2              YYY             HR          1/1/2015         1/10/2015

and I need to exclude the other 2 rows because i need to display employees who worked only on one designation and exclude if he had worked on 2 designations.  This has to be done from report level as we don't have access to Universe. This is urgent requirement.

Thanks in Advance.